The present invention relates to a system for spacing bottles on a horizontal, moving conveyor where the bottles have received wrap-around heat shrinkable labels thereon. The bare bottles are moved through a label applicating machine which adheres the leading edge of a plastic sheet label to the side of the bottle and then rolls the bottle along the length of the label carried on the exterior of a rotating vacuum drum. The trailing vertical edge of the label has a solvent for the plastic applied thereto and this trailing edge is overlapped and thereby adhered to the leading edge. After the bottle has been provided with the label, it is necessary to pass the bottle with label through a heat tunnel to shrink the tubular label to the external configuration of the bottle. This may include shrinking about the heel portion and shoulder portion of a generally cylindrical side wall beverage bottle such as a beer or soft drink bottle.
The plastic label may be formed from a web of foamed polystyrene material with printed indicia on one face thereof. The opposite face of the label will have a methylene chloride or trichloroethane solvent applied at finite areas thereof, usually a pair of vertically spaced areas at the leading edge of the label and a full height area at the trailing edge thereof.
Once the label has been adhered to the bottle and itself, it will exit the label wrapping machine on a horizontal conveyor which will carry the bottle to and through an infrared or other type shrink tunnel or oven to heat shrink the label to the bottle shape.
One such heat shrink tunnel is disclosed in U.S. patent application Ser. No. 690,557, filed Jan. 11, 1985 now U.S. Pat. No. 4,579,614, issued Apr. 1, 1986, in which the bottles with labels are carried on a conveyor through the oven without requiring rotation of the bottles to insure even shrinkage. This tunnel or oven utilizes infra-red heaters along each side of the conveyor with recirculating air heated by the heaters, constantly blowing across the line of bottles moving through the oven. One problem that has been encountered is that if the bottles become too closely spaced or are touching each other the air is able to reach only the sides of the bottles that are facing the heaters and blowers while the adjacent sides, in line with the bottle movement, may not receive enough heat to adequately shrink the sleeves or labels in the relative short time that the bottle is within the oven.
The typical oven may be 5.5 feet long and the bottles may be passing therethrough at a rate of 450 per minute. Thus, an individual bottle may be exposed to the heat for only about two seconds.
It has been suggested that the spacing of the bottles before entry into the oven or tunnel can be done by pocketed starwheels or other complex mechanical systems.
With the foregoing in view, it is an object of the present invention to provide a simple system not requiring mechanically driven mechanisms for spacing the bottles on the conveyor that extends from the label wrap machine to the heat shrink tunnel.
It is a further object of this invention to pass the bottles from the wrap machine through a set of opposing brushes to effectively release the bottles at precisely spaced intervals as they enter the heat shrink tunnel.
Other and further objects will be apparent from the following description taken in conjunction with the drawings.